[Registry-based comparison of multiple sclerosis epidemiology trend data in 1999 and 2019: the case of Yaroslavl]

To compare the epidemiological indicators of multiple sclerosis (MS) in Yaroslavl when comparing the 1999 and 2019 registers to study the pathomorphism of the disease in this territory.

During the work, the data of the 1999 and 2019 registers were used, including the age of the debut, the date of diagnosis, the form of the disease, clinical characteristics, the treatment received and its duration. In 1999, 257 patients living in the city of Yaroslavl (155 women and 102 men) were included in the MS registry with a reliable diagnosis of MS according to Poser's criteria with confirmation according to neuroimaging data. In 2019, 479 people living in the territory of Yaroslavl (342 women and 137 men) were included in the register with a diagnosis of MS based on the criteria of MacDonald 2005, 2010, 2017. As of 01.01.19, 970 patients (530 women and 440 men) were included in the patient register of the Yaroslavl region.

Clinical and epidemiological review of Yaroslavl MS Registry data in 1999 and 2019 showed significant changes in disease pattern. The prevalence rate increased from 42.6 to 78.5 cases per 100,000 people. The morbidity rate rose from 1.58 to 3.28 cases per 100,000 people. The reasons for the increase are improvement in the diagnostic quality, new diagnostic criteria and the true growth of prevalence and morbidity. The use of disease modifying drugs (DMDs) has extended «the time to EDSS 3,0» by 4 years, «the time to EDSS 6,0» by 5-8 years.